Airplane engine



June 2, 1931.

J. M. RQYAL AIRPLANE ENGINE Jim's M E0222 Filed Feb. 6. 1929 3 Sheets-Sheet l June 2,' 1931. J. M. ROYAL AIRPLANE ENGINE Filed Feb. e, 1929 5 Sheets-Sheet 2 I 11; max/v: 7

June 2, 1931. J. M. ROYAL AIRPLANE ENGINE FilefifFeb. 6, 1929 3 Sheets-Sheet 3 wmvmrr J I'MEs/ f 720m;

Patented June 2, 1931 UNITED STATES PATENT OFFICE Application filed February 8, 1928. Serial No. 888,014.

the actual use of motors of these types, is-

that these motors have a relatively great wind resistance making them undesirable for incorporation with certain types of air craft, and their weight is so distributed as often to require many undesirable compromises in desi which the designing engineers would readily avoid if it were possible.

Another disadvantage is that these types of motors are manufactured of the lightest material possible consistent with strength, and the mass also decreased wherever ossible while still maintainin the requlsite theoretical strength. This lig tening process has-now been carried almost to a conclusion and still the industry finds a very great need for still lighter power-plants.

This manner of lightening motors results in a motor wherein the moving parts are very apt to break under an slight unusual strain. To overcome this disa vantage, it is necessary to employ the most careful workmanship and all of this adds very greatly to the cost of aviation motors, and this is so much the case that it is considered among aviation experts that one of the greatest factors in arresting the progress of commercial aviation is the present excessive cost of motors.

One of the principal objects of my invention is the provision of an internal combustion type of motor wherein a relatively large work output results per unit of weight.

Another object is the provision of such a motor which may be economically manufactured without the necessity of disproportionately sacrificing the mass of the movin parts.

Another object of the invention is t e roduction of an improved type of motor 0 ering relativel slight wind resistance.

Another 0 ject of the invention is the pro- '55 vision of a motor wherein the arts are interchangeable and may be quic y and easily assembled.

Another object is the provision of an internal combustion motor wherein the parts therieof may be produced largely of pressed s cc Another object is to provide an improved two cycle motor particularly adapted for aviation work.

Another object is to provide an improved cooling and scavenging system for a two cycle motor.

These objects and the manner in which they are accomplished, together with additional 7 objects and features, will be apparent from a consideration of the following detailed description taken with the accompanying drawings, wherein Fig. 1 is a longitudinal sectional view showlng one embodiment of my invention;

Fig. 2 is a sectional view through the outside casing and taken along the line 2-2 of Fig. 1, part of the mechanism being shown in elevation;

Fi 3 is a vertical central section along the line 3-3 of Fig. 1;

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 1, looking in the direction of the arrows, and

Fig. 5 is an enlarged fragmentary sectional view taken alon the line 55 of Fig. 1.

Fig. 6 is a re uced vertical sectional view through Fig. 1.

Referring now to the drawings, the prescut embodiment comprises 'front and rear assembly plates 10 and 11 respectively, into which-cylinders 12-12 are adapted to extend in the manner shown. These cylinders are arranged concentrically about the center of the assembly plates and the centers of the plates are provided with large apertures through which the threaded ends of a sleeve 13 extend, this sleeve being secured in position by nuts 14 and 15. Within the sleeve 1 a shaft 16 is disposed having its ends projecting beyond the sleeve and provided with radial bearings 17 and 18, the two races of said bearings engaging the inside surface of the sleeve and the outside shaft surface I respectively.

A cylindrical central casing 19 engages v around and is eo-e'xtensive with the assembly drical casing 23 is provided having an en easing plate 24 fully enclosing the end of the shaft and all the mechanism at the rear of the motor.

Instead of the conventional type of motor wherein a cylinder head and single reciprocating cylinder are provided in each cylinder, I provide co-acting pistons moving away from each other and avoid the use of a cylinder head, with a mechanism for conveying the motion of the pistons to the single shaft.

In each of the cylinders are provided opposed pistons 26 and 27 equipped in a suita ble manner with the usual rings and the like.

Each one of the pistons has connected there- .to by means of a ball type joint, a connecting rod 28 having at its outside end, a ball 28a --forming a connection with an instrumentality, which will now be described.

The means for transmitting the motion of the connecting rods 28 to the shaft 16 is the same at each end of the motor and accordingly they will be described as if they constituted a single mechanism, as the two ends of the motor in this respect are essentially alike.

Immediately adjacent the bearing 17, a wabbler plate 29 is secured to the shaft 16 by any suitable means as for instance, by a key 31. This wabbler plate 29 is in the form of a disc with a central but obliquely disposed aperture therein, causing it to fit at an angle on the shaft 16. In other words the true axis of the disc is at an angle to the axis of the shaft.

The outer edge of the wabbler plate 29 is grooved to receive an inner race 32 of a ball bearing of a combination radial and thrust type, the outer race being designated by the reference character 33 and a double race of balls 34 being provided between the two races. A driving ring 36 surrounds the wabbler plate and engages the outer race 33. This wabbler driving ring is preferably formed of two parts suitably held together, with sockets therebetween for receiving the balls 28a so as to form a universal joint connection with the rods 28.

In order to prevent the driving ring 36 swivel connections 38 and 39 with the driving ring and a swivel connection 41 with the casing or housing 21. This yoke permits a free wabbler motion of the driving link 36 but prevents any turning thereof due to its normal tendency to .turn with the shaft. This arrangement is the same for both ends of the motor except of course the wabbler plates incline in opposite directions so that they will appear at all times as indicated in the drawings.

The space within the confines of the assembly plates existing between the casing 19 of the cylinder is made use of to supply a combustible mixture to the cylinders and also as a scavenging and cooling chamber. In order to simplify theexplanation of the present arrangement, the manner of supplying fuel to the cylinders will first be described.

Within the casing 19 and disposed a proper distance from the assembly plate 11, I provide an auxiliary separating plate 42, so that the entire space between this plate and the assembly plate 11 may be employed in' lieu of an intake manifold. Immediately adjacent this auxiliary separating plate, a plu rality of ports 4343 are provided in the cylinder so that when the pistons reach their extreme end position these ports will be uncovered so that the combustible mixture within the intake chamber may be forced thereinto in accordance with the relative pressures within this chamber and the cylin- The manner of supplying the combustible mixture to this chamber may be varied very greatly while still maintaining the general features of the invention. I provide any suitable type of carburetor (not shown) the vaporized mixture from which is discharged into the intake opening 44 of a suitable compressor 46. This compressor is of any suitable type, the one in the drawings being shown as comprising a casing havring journaled therein a shaft 47 on which are secured compressor blades 48. Shaft 47 is driven by a pinion 49 meshing with an idler 51, the idler being driven by a gear 52 which rotates with the shaft 16. This gear train [is simply illustrative, however, as greatly modified means may be employed to secure the same results.

At the opposite ends of the cylinders from the intake ports 43, a plurality of discharge ports 53 are provided, these ports being so disposed with respect to the pistons that when the piston 26, for example, approaches the end of its outward stroke, these ports are uncovered thus permitting the scavenging of the burnt gases due partly to their own expansion, and, after the intake ports 43 are uncovered to the pressure of the incoming charge as it is driven through the instrumentality of the compressor 46.

This represents the entire scavenging means but in connection therewith, I have provided a cooling system which makes use of the motion of the exhaust gases to bring a supply of cool air into contact with the cylinders to cool the same. This featureytogether with other cooling features, forming a part of the invention, will now be described.

The outer caslng 19 has a series of ports 56 around one end thereof with a similar series ject thereinto so that as the exhaust gases pass through the siphons 58 into the siphon casing 59, the air aroundthe discharge orifice of the siphon is caused to move with said gases, thus giving rise to a general movement of the air throughout the interior of the easing 19 substantially as indicated by the arrows. This air of course enters through the ports 56 and 57 and moves around into contact with the surfaces of all of the parts within the casing 19 so as to extract the heat therefrom. An auxiliary deflector 19a forming a part of the main casing keeps the air confined in contact with the cylinders.

It Will be seen that since the movement of the gases into the cylinders and out of the same in the form of burnt gases is always in the same direction, the cylinders will tend to be hotter toward one end than toward the other. In other words greaterheat tends to exist in the region of the exhaust end of the cylinders than in the intakeend. The arrangement of the siphons 58 tends to obtain a greater flow of air past this point than past the other portions of the mechanism and accordingly more heat is removed therefrom. In addition, the arrangement of the siphon casing 59 with the ports 57 contiguous thereto has the effect of bringing a supply of fresh cool air at all times into contact with the hotter portions of the cylinders.

It will be seen that the movement of the air by the siphons 58 is only between the as sembly plate 10 and the auxiliary plate 42. In other words, the portion of the cylinders between the assembly plate 11 and this auxiliary plate is not included in the cooling system. It is to be noted, however, that this portion of the casing acts as the intake manifold and at all times has the incoming charge circulating therethrough and this has a cooling effect. Very great cooling at this place is not necessary on account of the continuous flow of gases toward the exhaust end of the cylinders. Whatever cooling is effected by the incoming charge coming in contact with the warm outer surfaces of the cylinders not only is of advantage in' effecting a partial cooling, but it brings the gases to the proper temperature for obtaining the most complete burning of the gases in the cylinders, and the most efiicient operation of the motor.

As an auxiliary cooling means I have provided an arrangement whereby the piston heads are air cooled. The specific arrangement which I show comprises air passageways 62 and 63 on the outside of the motor casing, and having conduits 6464t connected thereto and extending through the casing and then projecting at right angles toward the inside of the pistons. Air under pressure is provided in the air passageways 62 and 63 and a constant blast of air is directed against the inside of the pistons in the manner shown through parts 65a inthe web 65 forming a part of the piston. 'Any suitable openings in the casing are provided for the escape of the air so introduced, or if desired it may be permitted to escape simply through the ordinary joints between the various portions of the casing.

In supplying the air to the assageways 62 and 63 the flow thereof may be regulated to obtain just the amount of air required. This air tends to supplement the cooling obtained by the siphon principle, or in certain respects it may be used entirely with other air or water cooling means provided for cooling the cylinder walls. Directing a continuous blast of air against the piston in this manner tends to keep the head thereof cooled thus avoiding the possibility of pre-ignition as is often inclined to take place if the head of the piston is overheated, particularly if it happens to have a slight deposit of carbon.

Any proper oiling system of course can be employed with a motor of this design, the oiling system of course having the usual oil reservoirs and oil pump (not shown). The usual type of oil lines are provided leading to the various moving parts all of which may be of standard form.

The particular arrangement of the wabbler plates, however, requires the arrangement of an oiling system which will be effective to supply sufficient oil thereto, and all of the mechanism associated therewith to produce proper operation without unnecessary wear. This arrangement will be substantially the same for both plates and accordingly explanation will be made as if only a single plate were used.

Oil under pressure is supplied from a suitable pump to an oil line 66 which is connected to an oil passageway in the pivot 41 of the yoke 37, this passageway connecting with an oil passageway 67 extending the full length of the yoke and connected through intermediate passageways to an annular passageway 68 in the driving ring 36 whence radial passageways 69 lead to the balls 28a on the connectingrods 28. From the passageway 68 a suitable supply, of oil may be fed'to the ball race, and any suitable system may be utilized for supplying oil to the other moving parts.

The piston 28, for example, may be made hollow so that a full force feed may be had to the universal joint connection (wrist pin) on the piston.

The motor as shown is adapted to operate on a two cycle principle usinlg a standard motor fuel such as asoline. n this event the charge is ignited by the usual spark plugs 71 controlledby any suitable timing mechanism (not shown) A motor of this design, however, may be operated on the Diesel principle and very good results obtained. Diesel motors as far as know have never been used for aviation work but I anticipate that by slight modifications in the structure herewith presented I can attain very great efliciency with crude oil fuel. I expect with this idea in mind to increase very greatly the cruising radius of the present commercial type of airplanes.

The operation of the motor should be clear from the receding description. The pistons are broug t together by the reverse action of the two wabbler plates to compress the gas between .them in the region immediately adjacent the spark plug. Slightly before final compression (the exact time of course de-- pends on the timing desired) the spark plug is energized to ignite the charge. As soon as the wabbler plates are in proper position the resultant expansion of the gases drives the pistons apart until the exhaust ports 53 begin to be uncovered. The exhaust now escapes through these ports and as soon as the intake ports 43 are uncovered the combustible mixture under pressure is forced into the cylinder and drives the burnt gases out by the force of their entrance. At the time that the scavenging is completed the pistons are again driven inwardly to cover the ports and again compress the new charge. The speed of the compressor 46 and consequently the pressure of the incoming mixture depends upon the speed of the motor. In this way when the motor is running slowly the flow of gases is slow and the reverse is true when the motor is running at high speed. Accordingly the timing of the piston however is such that substantially complete scavenging takes place at each stroke of the motor independent of the speed thereof.

Although I have described the specific details of my invention in order to make same clear to those skilled in the art, it is obvious that I do not restrict myself to the particular details described and the invention is limited only by the scope of the appended claims.

What I claim as new anddesire to protect by Letters Patent of the United States 15 1. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders formed of steel tubing, a pair of mutually coacting pistons in each cylinder, means for converting the motion of the pistons into reciprocating movement,

pressed steel supporting means for the cylinders and a pressed steel outer casing adapted to cooperate with the cylinder supporting gieaals to form an intake band and a cooling 2. An internal combustion motor having a plurality of radially disposed longitudinally aligned cylinders, a pair of mutually co-acting pistons in each cylinder, a centrally disposed shaft with a pair of wabbler plates one at each end of the cylinders, connections from the pistons to the wabbler plates for driving the shaft supporting means for the cylinders and an outside casing cooperating with the supporting means to form an intake passageway and a cooling belt completely enclosing the cylinders. 1

3. An internal combustion motor having a plurality of radially disposed longitudinal ly aligned cylinders, a pair of mutually coacting pistons in each cylinder, a centrally disposed shaft with a pair of wabbler plates one at each end of the cylinders, connections from the pistons to the wabbler plates for driving the shaft supporting means for the cylinders and an outside casing cooperating with the supporting means to form an intake passageway and a cooling belt completely enclosing the cylinders, the supporting means for the cylinders and the outside casing being formed of pressed steel.

4. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders, an assembly plate supporting the cylinders at each end, a centrally disposed shaft, a pair of mutually coacting pistons in each cylinder means for transferring the movement of the pistons to the shaft, an auxiliary separating plate between the assembly plates with its plane parallel to the planes of said assembly plates, and a housing band disposed about the auxiliary plate and one assembly plate, the space so confined serving as an intake passageway for supplying combustible mixture under pressure to the cylinders.

5., In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders, an assembly plate supporting the cylinders at each end, a centrally disposed shaft, a pair of mutually coacting pistons in each cylinder means for transferring the movement of the pistons to the shaft, an auxiliary separating plate between the assembly plates with its plane parallel to the planes of said assembly plates, and a housing band disposed about the auxiliary plate and one assembly plate, the space so confined serving as an lntake passageway for supplying combustible mixture under pressure to the cylinders, intake parts being provided in the cylinders communicating with said intake passageway.

6. In an internal combustion motor. a plurality of radially disposed longitudinally aligned cylinders, an assembly plate supporting the cylinders at each end, a centrally disposed s'haft, a pair of mutually coacting pistons, in each cylinder means for transferring the movement of the pistons to the shaft, an auxiliary-separating plate between the assembly plates with its plane parallel to the planes of said assembly plates, and a housing band disposed about the auxiliary platemeans for moving a band of air through said' casing in contact with the cylinders to cool the same.

7. In an internalcombustionmotoraplurality of radially disposed longitudinally aligned cylinders, an assembly plate supporting the cylinders at each end, a centrally disposed shaft, a pair of mutually coacting pistons, in each cylinder means for transferring the movement of the pistons to the shaft, an auxiliary separating plate between the assembly plates with its plane parallel to the planes of said assembly plates, and a houslng band disposed about the auxiliary plate and one assembly plate, the space so confined serving as an intake passageway for supplying combustible mixture under pressure to the cylinders? a central casing enclosing the greater portion of the cylinders, and means for moving a band of air through said caslng in contact with the cylinders to cool the same, and deflectors on the inside of the casing, one between each pair of cylinders, for'confining the moving air to increase its contact with the outer cylinder walls.

8. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders having intake ports near one end thereof and exhaust ports near the other end, a pair of mutually coacting pis tons in each cylinder an impeller shaft, means for transmitting the motion of the pistons to the shaft, means resulting in the formation of a closed chamber surrounding the intake parts adapted to hold combustible mixture under pressure, means forming a cooling chamber surrounding the greater portion of the cylinders, and means for utilizing the action of the cylinder exhaust to maintain a movement of cooling air through said cooling chamber.

9. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders having intake ports near one end thereof and exhaust ports near the other end, a pair of mutually coacting pistons in each cylmder an impeller shaft, means for transmitting the motion of the pistons to the shaft, means resulting in the formation of a closed chamber surrounding the intake parts adapted to hold combustible mixture under pressure, means forming a cooling chamber surrounding the greater portion of the cylinders, and means for utilizing the acting of the cylinder exhaust to maintain a movement of cooling air throu h said cooling chamber, longitudinally of 51c cylinders, the general direction'of movement of said air being from the intake end of the cylinders and toward the discharge on 10. In an internal combustion m'otor a a plurality of radially disposed longitudinally aligned cylinders having intake ports at one end and exhaust ports at the other end thereof, means for supplying combustible mixture under pressure to said intake ports, air siphons connected to receive the scavenged gases from the exhaust ports, an auxiliary casing having the air siphons projecting theremto so as to cause a movement of air with the exhaust through said auxiliary casing, and an outside casing having air passageways positioned to cause the air moved by said siphons tobe drawn through said passageways and moved longitudinally of the cylinders.

11. The combination described in claim 10 wherein said ports are disposed entirely around said cylinders, withspace' between each pair of ports.

12. The combination described in claim 10 wherein said exhaust ports are disposed entlrely about the cylinders with the air siphons so secured thereto as to permit the movmg cooling air to-contact with the cyllnders between the exhaust ports to prevent overheating of the cylinders in the region of said ports.

1 3. In an internal combustion motor a plu rality of radially disposed cylinders longitudinally aligned with a centrally disposed shaft, a pa1r of pistons in each cylinder,

means connecting the pistons to the shaftto drive the same, an intake passageway entirely surrounding and enclosing one end of the cylinders and an exhaust passageway surrounding the other end, the cyllnders having slots disposed entirely-around the same 1n two sections one near each end thereof, torserve as intake and exhaust par s, a coo ing passa ewa havin orts at the end near the intak e pas sagewai and air siphons connected to the exhaust ports and extending into the exhaust passa eway so that a bodily movement of air ta es place longitudinally of the cylinders from the ports in the cooling passagewa out through the exhaust assageway, the intake end of the cylmders ing partially cooled by the incoming char e.

l4. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders, a pair of mutually coacting pistons in each cylinder, an annular passageway for cooling air adjacent the ends of the cylinders, and a jet with one end conneoted to one of the annular air passageways and the other end thereof disposed to discharge cooling air against the back of a piston head.

15. In an internal combustion motor a plurality of radially disposed longitudinally aligned cylinders, an intake passageway for combustible mixture enveloping one end of the cylinders, an exhaust passageway near the other end thereof, means for causing a longitudinal movement of the body of air from the intake passageway along the cylinders to the exhaust passageway, a pair of mutually ooacting pistons in each cylinder, an annular passageway for cooling air adjacent the ends of the cylmders, and a at with one end connected to one of the annular air passageways and the other end thereof disposed to discharge cooling air against the back of a piston head.

In witness whereof, I hereunto subscribe my name this 5th da of January 1929.

J AMES M. ROYAL. 

